One known bearing mounting mechanism includes a sleeve, nut, and washer locking mechanism. This design uses a sleeve with a straight bore and tapered outer surface which fits onto the shaft. One end of the sleeve outer surface has a threaded portion and there is a slit through the entire axial length of the sleeve. The bearing inner ring bore has a taper which matches the sleeve outer surface. The bearing is driven up the tapered sleeve with a nut that threads onto the tapered sleeve. This compresses the sleeve and locks the bearing to the shaft. A lockplate is then used to keep the nut from rotating and loosening from the sleeve. The bearing is dismounted by removing the lockplate, loosening the nut and driving the bearing back down the taper.
Another mechanism uses a tapered sleeve and tapered inner ring bore as described above but has a nut that is held captive to the inner ring. This design is installed by turning the nut and driving the bearing up the tapered sleeve. Once the bearing is tight, a lockplate is used to secure the nut and prevent rotation. To remove this bearing, the lockplate is removed and the nut is rotated in the opposite direction. The nut is held to the inner ring so this rotation drives the bearing down the sleeve and it becomes loose to the shaft.
Another mechanism requires the use of two tapered sleeves and an inner ring with two matching tapers. The tapers on the inner ring begin with a thin cross section at each end of the bearing, both increasing in thickness until they meet in the center of the bore. The first tapered sleeve extends through the entire bearing inner ring and contains a threaded portion on each end. The second tapered sleeve extends only to the center of the bore and slips over the extended length of the first tapered sleeve. The second tapered sleeve is held captive in the first threaded nut. For installation, the second tapered sleeve is installed over the first tapered sleeve and the first threaded nut engages the first threaded portion of the first tapered sleeve. This action pulls the first tapered sleeve into engagement with the first inner ring taper and pushes the second tapered sleeve into engagement with the second inner ring taper which compresses both sleeves causing the bearing to become tight to the shaft. At this point a screw on the first threaded nut is tightened to prevent rotation and loosening. For removal, the screw on the first threaded nut is loosened. The first threaded nut is loosened from the first tapered sleeve and the second tapered sleeve is removed from the bearing. The second captive nut is then threaded onto the second threaded portion of the first tapered sleeve which removes the first tapered sleeve from the bearing causing the bearing to become loose to the shaft.
Another mechanism uses a sleeve with a straight bore and a multiple tapered outer surface. The inner ring has a multiple tapered surface to match the sleeve. The sleeve extends from both ends of the inner ring. Each side of the bearing has a washer which rests against the end face of the inner ring. The sleeve outer diameter on both ends has a recessed slot. A flange sits inside that slot on both sides. Each flange has threaded holes containing setscrews. To install the bearing the mounting side flange is used, the setscrews are tightened which move the sleeve axially and drive the bearing up the tapered surface tightening it to the shaft. To remove the bearing, the mounting side flange is loosened and the dismounting side flange is engaged. As these setscrews are turned toward the bearing, the sleeve moves in the opposite axial direction loosening it from the shaft.
The first limitation of the prior art is obtaining the proper axial movement to tighten the bearing to the shaft while not over tightening the bearing. If the bearing is over tightened then the necessary clearance in the bearing will be reduced or removed causing decreased life. The sleeve, nut, washer and captive nut designs encounter this problem. They use the “turn of the nut” tightening method, which provides a specific amount of rotation to apply to the nut in order to obtain the proper shaft lock. This method skews the accuracy of the shaft lock because it relies on the consumer's personal judgment of a “zero point”, which differs between each user. The “zero point” is often defined by the manufacturer as when the nut is “hand tight”. Other manufacturers require the user to tighten until the nut is “tight”, giving no quantitative value to tighten to. Both methods yield variation between installers which will cause variation in the bearing internal clearance and ability to lock the bearing to the shaft.
The other major limitation with prior solutions is the method of dismounting the bearing from the shaft. The sleeve, nut, washer assembly provides no means of removing the bearing from the shaft. To remove the bearing, the nut is loosened from the tapered sleeve and then the bearing must be driven down the sleeve. This is accomplished by hitting either the shaft or bearing with a hammer to release the sleeve from the bearing. This often does not work and the bearing must be cut off the shaft which may damage expensive shafting and can add additional machine downtime. The multiple tapered sleeve and multiple sleeve designs utilize a separate mechanism for mounting and dismounting the bearing. The dismounting mechanism is on the opposite side of the mounting mechanism. This is undesirable in many applications due to a lack of space or access to the back side of the bearing. In these applications the dismounting feature of this bearing is not usable.
It may be beneficial to incorporate a means of tightening a bearing to a shaft using a sleeve that concentrically constricts around the shaft. It may be desirable to incorporate certain design considerations such as easy installation, easy removal, minimal pieces, high strength, small size, and cost effectiveness. A need may exist for a locking mechanism that would feature some or all of these design considerations.
The disclosure provides a means to secure the bearing to a shaft. The design provides a concentric locking mechanism to minimize the amount of raceway distortion caused by the locking mechanism. This design also provides a means to secure and remove the bearing on one side of the bearing using the same set of components. The disclosure also uses a metered torque tightening approach to ensure the proper installation.
The present disclosure provides a mechanism for mounting and dismounting a bearing to a shaft. The mechanism includes a split sleeve and a receptive flange adapted to be axially fixed to the bearing. A positioning flange is coupled to the split sleeve to form a tapered bushing assembly. At least one screw extends through at least a portion of the positioning flange and the receptive flange. The screw threadingly engages one of the positioning flange and the receptive flange. Rotation of the screw in a first direction axially drives the sleeve into engagement with the bearing to collapse the split sleeve into engagement with the shaft. Rotation of the screw in a second opposite direction axially pulls the sleeve out of engagement with the bearing to return the sleeve to a more undeformed state. The sleeve is released from engagement with the shaft.
Additionally, the present disclosure provides a mechanism for locking a bearing to a shaft including a split sleeve having a radially extending flange formed at one end. The flange includes first and second bores. The second bores include internal threads. The split sleeve has a tapered surface adapted to engage the bearing. A first screw extends through the first bore and is adapted to threadingly engage the bearing. Rotation of the first screw axially drives the tapered surface into engagement with the bearing to collapse the split sleeve into engagement with the shaft. A second screw is threadingly engaged with the internal thread of the second bore and is adapted to engage the bearing. Rotation of the second screw axially drives the tapered surface out of engagement with the bearing to allow the split sleeve to be moved relative to the shaft.
A method of locking a bearing to a shaft includes coupling a positioning flange to a split sleeve. A receptive flange is coupled to the bearing. A screw is threadingly engaged with a threaded bore formed in one of the positioning flange and the receptive flange. The screw is rotated in a first direction to axially translate the split sleeve into engagement with the bearing to collapse the split sleeve into engagement with the shaft.